Wednesday, December 16, 2009

F5K meet automatic RCS-4 antenna switch

I modified my Ameritron RCS-4 a few years ago to try and make it auto band switching. I've described the RCS-4 before. It is a cleaver antenna switch that uses 4 states to switch 4 antennas using only the coax as a signal line to the remote switch. What gets sent down the coax is the RF plus +12V -12V 12V AC and no volts. Each of those 4 signals tells what relays to turn on in the switch.

I modified the switch to use with my Orion and had mixed results. Most of the switch combinations would work fine, like going from 160 to 40, but there were some combinations that would blow the fuse. I had a similar experience using the X2 port with my SDR-1000. I was able to defeat this flaw by turning off the power to the control head, do the band switching then power back up so I knew there was a way to make this work using a 555 one shot.

This morning I couldn't sleep. I get some arthritis pain in my hands sometimes and it gets bad enough I have to get up. I recently got the USB2LTP port running on my F5K and I wired up the UMS band decoder board to my shiny new LPT port and did some ohm meter checks using the F5K through DDUTIL as the switching device. No problem. I can easily decode BCD data from DDUTIL and I now have up to 11 possible antennas I can control based on freq i.e up to 11 band following antennas. DDUTIL has another feature that is quite nice. It has a way to manually generate the BCD by clicking a little software switch. What that means is I can auto band follow OR I can choose a particular antenna all the time so for example I can load up my 20M vert when I am on 17M using a tuner by manually choosing the 20M setting on my antenna switch even though my F5K is on 17M. Very handy!!

I tell you what, that Steve K5FR thinks of just about everything!

Now came the acid test. Since I couldn't sleep I reverted to form and decided to see if I could blow some fuses. I have a hand full of 1 amp fuses in the drawer for just such an occasion. I opened up the RCS-4 control box and traced out my modification (I couldn't remember exactly how I wired it) and then hooked up about half a dozen clip leads between the UMS board and the RCS-4 control head.

With the distant relay box disconnected from the control head I was able to band follow perfectly using the F5K. Now came the moment of truth because it was when I connected the remote switch that I would blow them damn fuses. The bands switch and NO fuses blow. No timer needed.

So what is the point of all this? I have an auto band switching radio now, but more importantly we now have a reliable cheap way to get band data OUT of the F5K using DDUTIL, the LPT port and the UMS board, and it works perfectly, and it can be remoted. No need to wait for Flex wire to be developed. Flex wire has many more potential features but for now all I want to do is get some band data out of the radio and this setup does the trick in spades for cheap. Maybe in some future life I will worry about Flex wire rotor controllers. For me now DDUTIL is the nuts. It totally makes my station get up and do the boogaloo.

This will also work with the F3K and any other PSDR radio that works with DDUTIL.

So if you want to let the XYL know what you want for Christmas tell her to get you a USB2LPT port and a UMS band decoder board, and go have a blast automating your station

We are in the process to see if we can get this to become a full fledged SO2R set up that will be able to switch up to 2 banks of 11 antennas, set power, set rotor use band following amps etc etc. There has to be some mods done to PSDR to get that job done but hopefully we can move forward on this and make this radio into the contest, DXing machine it is destined to be. I presently have the hardware working for 2 x 11 antennas, but some software needs to be massaged to get the radio to see eye to eye with my needs.

Call to arms

Hear Ye Hear Ye

If you're interested in writing something interesting for this blog regarding your SDR experience let me know. I would like to include things like how your SDR contest station is set up, or your VHF station that uses SDR as the system center, feats of weak signal work or how well the SDR works in various challenging situations. If you are a foreign ham and would like to comment on the growth of SDR in your particular part of the world. Bring it on!

I reserve the right to publish or not, but I'm pretty open to documenting a wide variety of honest experiences from users, for readers to explore. The understanding of SDR in our hobby is so nascent, that I want the reader to be able to see the value of SDR through the eyes of YOUR experience and enthusiasm.